//
//  SQLiteDataBaseManager.m
//  18-SQLite
//
//  Created by dllo on 16/8/8.
//  Copyright © 2016年 LST. All rights reserved.
//

#import "SQLiteDataBaseManager.h"
#import "Student.h"
@implementation SQLiteDataBaseManager
// 单例创建方式, 只有一个对象
// 内存管理中, 单例不能被释放
+ (SQLiteDataBaseManager *)sharedManager {
    static SQLiteDataBaseManager *manager = nil;
    // 保证线程安全, 只执行一次
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        manager = [[SQLiteDataBaseManager alloc] init];
    });
    return manager;
}

- (BOOL)openSQLite3 {
    NSArray *pathArray = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *document = [pathArray firstObject];
    // 数据库SQLite3文件类型 .db
    NSString *dbPath = [document stringByAppendingPathComponent:@"student.db"];
    NSLog(@"%@", dbPath);
    // UTF8String 属性, 将oc字符串转成C字符串
    // 参数1: 数据库文件路径
    // 参数2: 指向指针的指针, 该指针可以被修改
    int result = sqlite3_open([dbPath UTF8String], &dbpoint);
    // sqlite3_open 当路径文件不存在时, 文件会被SQLite创建并打开
    // 当路径文件存在时, 文件被直接打开
    // sqlite3_open 返回值为int型, 0 SQLITE_OK 代表成功, 1代表失败
    return [self isOpeerationResult:result alertText:@"打开数据库"];
}



- (BOOL)closeSQLite3 {
    // 关闭数据库时, 如果数据库处于打开状态, 则正常关闭, 如果数据库处于关闭状态, 则显示失败, 原因21 库不存在
    int result = sqlite3_close(dbpoint);
    return [self isOpeerationResult:result alertText:@"关闭数据库"];
}
- (BOOL)creatTable {
    // SQL语句
    // 创建表
    // creat table 表名 (字段1 类型 约束, 字段2, 字段3)
    // NSString *createSQL = @"create table stu(stu_id integer primary key, stu_name text)";
    // primary key 一个表只能有一个主键
    // autoincrement 自增, 添加完该字段, 系统会自动创建一个数据库的表sqlite_seqence, 用来保存自增的值
    // not null 不能为空, 为空会报SQL错误
    NSString *createSQL = @"create table stu2(stu_id integer primary key autoincrement, stu_name text not null)";
    int result = sqlite3_exec(dbpoint, [createSQL UTF8String], NULL, NULL, NULL);
    return [self isOpeerationResult:result alertText:@"创建表"];
}

- (BOOL)isOpeerationResult:(int)result alertText:(NSString *)text {
    BOOL isOpeeration = YES;
    if (result == SQLITE_OK) {
        NSLog(@"%@成功", text);
        isOpeeration = YES;
    } else {
        NSLog(@"%@失败----%d", text, result);
        isOpeeration = NO;
    }
    return isOpeeration;
    
}
- (BOOL)insertStu:(Student *)stu {
    NSString *insertSQL = [NSString stringWithFormat:@"insert into stu1 values (%ld, '%@')",stu.stu_id, stu.stu_name];
    // 自增 autoincrement
    // 默认 如果填入NULL, 值会从1开始
    // 如果填入其他值, 会从其他值开始, 例: 填入100就会从100开始计算, 并进行存储
    // 存储在sqlite_sequence中
//    NSString *insertSQL = @"insert into stu1 values (110, '报答')";
    int result = sqlite3_exec(dbpoint, [insertSQL UTF8String], NULL, NULL, NULL);
    return [self isOpeerationResult:result alertText:@"添加"];
    }
- (BOOL)deleteStu:(Student *)stu {
    NSString *deleteSQL = [NSString stringWithFormat:@"delete from stu1 where stu_id = %ld", stu.stu_id];
    int result = sqlite3_exec(dbpoint, [deleteSQL UTF8String], NULL, NULL, NULL);
   // NSString *alertext = [NSString stringWithFormat:@"删除学号为%@的数", stu.stu_name];
    return  [self isOpeerationResult:result alertText:@"删除一条"];
}
- (BOOL)deleteAll {
    NSString *deleteSQL = @"delete from stu1 where 1=1";
    int result = sqlite3_exec(dbpoint, [deleteSQL UTF8String], NULL, NULL, NULL);
    
    return [self isOpeerationResult:result alertText:@"删除全部"];
}

- (BOOL)updateOldName:(NSString *)Oldname newName:(NSString *)newName {
    // update 表名 set 字段名 = 新值 where 字段名 = 旧值
    NSString *updateSQL = [NSString stringWithFormat:@"update stu1 set stu_name = '%@' where stu_name = '%@'", newName, Oldname];
    int result = sqlite3_exec(dbpoint, [updateSQL UTF8String], NULL, NULL, NULL);
    return [self isOpeerationResult:result alertText:@"更新"];
}
- (NSArray *)selectAll {
    // select 字段名, 字段名... from 表名 where 条件
    NSString *selectAll = @"select * from stu1";
    // 替身指针
    sqlite3_stmt *stmt = NULL;
    // 参数1 数据库指针 sqlite3 *
    // 参数2 SQL语句
    // 参数3 SQL语句的长度, -1 不限制
    // 参数4 替身, 查询出的内容, 放入替身中, 并将替身返回
   int result = sqlite3_prepare(dbpoint, [selectAll UTF8String], -1, &stmt, NULL);
    NSMutableArray *stuArray = [NSMutableArray array];
    // 如果查询结果为成功
    // step 查询替身中有没有其他数据,
    // 当包含有其他数据时, 结果为 SQLITE_ROW
    // 当不包含其他数据是, 结果为 SQLITE_DONE
    if (result == SQLITE_OK) {
        // 循环, 遍历替身内容,
        while (sqlite3_step(stmt) == SQLITE_ROW) {
            // 循环体中, 取对应的每一列数据
            // 取出第0列的数据, 根据类型选择函数, int
            int stu_id = sqlite3_column_int(stmt, 0);
            
          const unsigned char *stu_name = sqlite3_column_text(stmt, 1);
            Student *stu = [[Student alloc] init];
            stu.stu_id = stu_id;
            stu.stu_name = [NSString stringWithUTF8String:(const char *)stu_name];
            [stuArray addObject:stu];
        }
    }
    // 循环结束后, 销毁替身
    sqlite3_finalize(stmt);
    return stuArray;
}








@end
